Defining Queues - Cisco SG200 Series Administration Manual

Quality of Service

Defining Queues

STEP 5
Defining Queues
Cisco Small Business SG200 Series 8-port Smart Switch
• trust ip-precedence—The port uses the IP Precedence value in the IP
packet header. If no value is provided, the default priority is assigned. Non-IP
VLAN tagged and untagged frames are assigned the default priority.
• trust ip-dscp—The port uses the DSCP marking in the IP packet header for
both VLAN tagged and untagged IP packets. Non-IP VLAN tagged and
untagged frames are assigned the default priority.
• trust all—For IP packets, the port uses the DSCP marking to determine the
priority. For non-IP frames, the port uses the 802. 1 p priority if the frame is
VLAN-tagged and the port default priority if the frame is not VLAN tagged.
Click Apply and then click Close. Your changes are saved to the Running
Configuration.
You can use the Queue page to configure how the traffic scheduler determines
which queue has access to the egress port. A queue can be configured in strict
priority mode or Weighted Round-Robin (WRR) mode. By default, all queues are
strict priority queues.
Packets are transmitted according to the following principles:
• Packets from the highest priority queue are transmitted first.
• If a queue is in strict priority mode, it is allowed to transmit until it has no
more packets or until a higher priority queue has packets to send.
• If a queue is in WRR mode, it is allowed to transmit a number of packets that
is proportional to its configurable weight value. The weight is expressed as
a percentage of the total bandwidth for each port.
A combination of strict queue and WRR queues can be configured at a port.
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